Carboxylic acid fluorides as pesticides

ABSTRACT

Carboxylic acid fluorides having a boiling point of preferably less than 100° C. are suitable for use as pesticides. Acetyl fluoride is highly suitable, and Chlorodifluoroacetyl fluoride and trifluoroacetyl fluoride are also very useful. Mixtures of carboxylic acid fluoride pesticides and other pesticides are also disclosed.

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation of international patentapplication no. PCT/EP00/09544, filed Sep. 29, 2000, designating theUnited States of America, the entire disclosure of which is incorporatedherein by reference. Priority is claimed based on Federal Republic ofGermany patent application nos. DE 100 41 425.7, filed Aug. 23, 2000,and DE 199 48 496.1, filed Oct. 7, 1999.

BACKGROUND OF THE INVENTION

[0002] The invention relates to the use of carboxylic acid fluorides aspesticides. It is known in the art to use sulfuryl fluoride as apesticide; see U.S. Pat. No. 2,875,127, for example. Pests or fungi canbe controlled, for instance, in installed or uninstalled buildingtimber, even in freshly cut timber. Buildings attacked by pests, such asbeetles or termites, as well as storage areas can be disinfested. Alsoknown is the disinfestation of museums, churches, or mills. It is alsoknown to use sulfuryl fluoride in combination with carbon dioxide, inertgases, or other pesticides.

[0003] In accordance with the invention it has been found thatcarboxylic acid fluorides can be used as pesticides. The term“carboxylic acid fluorides” preferably encompasses carboxylic acidfluorides containing a total of 2 to 7 carbon atoms. Preferred arealiphatic carboxylic acid fluorides. Compounds with a saturated alkylgroup are especially preferred. Also usable are carboxylic acidfluorides that have one or more carbon-carbon double or triple bonds.The alkyl, alkenyl or alkynyl group can also be substituted, e.g., by 1or more halogen atoms, e.g., 1 or more fluorine atoms. Particularlyuseful are carboxylic acid fluorides with a total of 2 to 4 carbonatoms, especially those with saturated alkyl groups. They can besubstituted by 1 or more halogen atoms, preferably chlorine and/orfluorine atoms. Particularly preferred carboxylic acid fluorides arefluorides corresponding to the formula RC(O)F, where R representsmethyl, ethyl, difluoromethyl, trifluoromethyl and difluorochloromethyl.The boiling point of preferred carboxylic acid fluorides is preferablyless than 45° C., especially less than 35° C.

[0004] If desired, the carboxylic acid fluoride can be used incombination with other pesticides (fumigants). Carboxylic acid fluoridecan, for instance, be used together with inert gases (nitrogen, noblegases) and/or carbon dioxide. The inert gases and CO₂ can serve asauxiliary gases, for example as carrier gases, e.g., in compounds with ahigher boiling point. Other fumigants can of course also serve ascarrier gases. However, inert gases and CO₂ also have pesticidalproperties. The carboxylic acid fluoride and the other fumigant(s)and/or CO₂ can be used premixed or separately, simultaneously orsuccessively, or overlapping in time. Preferred pesticides used inaddition also have a boiling point of less than 100° C. under normalconditions, preferably less than 45° C., particularly less than 35° C.Alternatively, an atomizing agent can be used. Carbon dioxide has theadvantage that the carboxylic acid fluoride concentration can bereduced, since carbon dioxide increases the toxicity of the carboxylicacid fluorides (increased respiration rate of the pests).

[0005] It is, of course, also possible to take measures that aretypically used in fumigation processes and are known per se. Forinstance, moisture can be reduced during fumigation, e.g., byintroducing drying agents (e.g., SiO₂) or by guiding the treatment gasatmosphere continuously or discontinuously across a drying agent.Fumigation may be carried out in several steps. For initial fumigation,the conditions, particularly with respect to the fumigant concentration,are selected so that the larvae and the adults are destroyed. The secondand possibly a third or additional fumigation steps are carried out ifeggs that were not previously destroyed develop into larvae or adults.It is known that the fumigant concentration to combat larvae or adultscan typically be lower than the concentration necessary to destroy eggs.If the concentration is selected such that only the larvae or the adultsare destroyed but the process is repeated several times whenever newlarvae or adults have developed, the use of fumigant can be reduced.

[0006] As an alternative, fumigation may also be carried out usingfumigants that are known ovicides, e.g., in combination with hydrocyanicacid, formic acid esters, alkylisothiocyanates or PH₃. If desired, thefumigation process may also be carried out in combination with atomizingagents, such as pyrethroids, as described in published German patentapplication no. DE-OS 197 47 648. As disclosed in Austrian Patent154,481, it is also possible to arrange a balloon in the room to befumigated so as to reduce the room volume and thus to save fumigant.

[0007] In the method according to the invention, one or more carboxylicacid fluorides can be used as the only pesticide. It is also possible,however, to use carboxylic acid fluoride(s) in combination with otherpesticides. For instance, carboxylic acid fluorides can be used togetherwith one or more pesticides selected from the group consisting ofsulfuryl fluoride, sulfuryl chlorofluoride, nitrogen, noble gases,carbon dioxide, carbonyl sulfide, PH₃, alkyl phosphines (mono-, di- andtrialkyl phosphines), SF₆, inorganic and organic compounds with the CNgroup, organic esters, organic nitro compounds, halogenatedhydrocarbons, alkynols, thiocyanate esters, isothiocyanate esters,chloropicrin, ethylene oxide, sulfonyl fluorides, and the aforementionedatomizing agents. The esters used are preferably alkyl esters, forinstance, alkyl esters of formic acid, acetic acid, etc. Chloropicrincan be used as a warning agent.

[0008] The usefulness of carbonyl sulfide as a fumigant is disclosed inU.S. Pat. No. 6,203,824 (=WO 93/13659). Suitable formic acid esters aredisclosed, for instance, in published German patent application no.DE-OS 197 47 640. Suitable acetic acid esters are described in publishedGerman patent application no. DE-OS 197 58 318. Suitable alkynols orthiocyanate esters are described in published German patent applicationno. DE-OS 198 01 332. Other carbonic acid esters are described also inpublished German patent application no. DE-OS 198 13 894. Useful nitrocompounds are set forth in published German patent application no. DE-OS198 04 508. Suitable sulfonyl fluorides are disclosed in German patentDE 196 33 595. Hydrocyanic acid and CF₃CN may also be used as COfumigants.

[0009] The pest control method according to the invention may be usedfor any purpose. For instance, rooms where the pests reside can befumigated, e.g., storage areas, museums, churches, mills, cargo holds ofships, railroad cars, and silos. Individual goods to be fumigated can beplaced into mobile tents. Mobile chambers, containers, even buildings,e.g., residential buildings, can be fumigated. It is of course useful toseal the corresponding rooms or containers, so that no fumigant canreach the environment. The containers or buildings can also be wrappedin foil in a known manner to prevent treatment gas from escaping intothe atmosphere. A seal to prevent gas exchange, as described in theInternet under http://www.morse-associates.com/pressure.html, in thechapter entitled “Relative Pressure in Work Area,” can also be ensuredby adhesive tape, strippable coatings, or caulking. Both installed oruninstalled building timber can be treated. For instance, freshly cut orsawed timber can be placed into a tent, a fumigation chamber, or a foilenvelope for fumigation. This can prevent the spreading of pests inexport/import (quarantine fumigation).

[0010] Preferably, the method according to the invention is used forcontrolling the known storage pests and material pests (particularlywood pests), e.g., the tobacco beetle, the grain weevil, moths, flourmites, rice weevils, deathwatch beetles, woodworms, house longhornbeetle, or carpet beetles. The method can also be used to controltermites.

[0011] The method according to the invention may also be used for soilfumigation. In this case, for instance nematodes and other vermin aredestroyed.

[0012] Measures that are typically used in fumigation may be taken,e.g., working at an elevated temperature. It is advantageous if thetemperature in pest control is at least 10° C., preferably between 15°and 35° C. The work is preferably done at a temperature that is atmaximum 3° C. below the boiling point of the compound. Particularlypreferred is fumigation at or above the boiling point. This is whycarboxylic acid fluorides with their relatively low boiling point areparticularly suitable for temperature-sensitive materials.

[0013] To achieve a high mortality rate of the storage, soil and woodpests as well as rodents, harmful insects or fungi to be controlled, theconcentration preferably ranges from 0.1 g/m³ to 200 g/m³, and theduration is adjusted accordingly. The higher the concentration, theshorter is the contact time required.

[0014] The treatment gas can be delivered via water or alkalinesolutions or alkali and is subsequently decomposed into harmlesscompounds. The gas may also be recovered through sorption, e.g., on amolecular sieve or activated carbon. Thermal decomposition or catalyticdecomposition (incineration, pyrolysis, high-temperature hydrolysis) isalso possible.

[0015] The invention also relates to mixtures of carboxylic acidfluorides and at least one other known pesticide. The preferredadditional pesticides are the aforementioned agents. Mixtures ofcarboxylic acid fluorides and CO₂, in the form of a gas, liquid orsolid, are particularly preferred. These mixtures may also containadditional pesticides.

[0016] The invention broadens the spectrum of useful fumigants, forwhich there is currently a desperate need, since MeBr has meanwhile beenfound to damage the ozone. Carboxylic acid fluorides act very quickly,which is of course advantageous in practice. After hydrolysis, acetylfluoride forms acetic acid, which is found in nature.

[0017] Carboxylic acid fluorides can be produced, for example, fromcarboxylic acid chlorides and HF adducts of amines as described inco-pending U.S. patent application Ser. No. 09/856,909 (=WO 00/32549),the disclosure of which is incorporated herein by reference.

[0018] The following examples are intended to illustrate the inventionin further detail, without limiting its scope.

EXAMPLES

[0019] General:

[0020] Pests used:

[0021] a) Storage Pests

[0022] a1) Mealworm beetle (Tenebrio molitor)=TENEMO

[0023] Size: 12-18 mm, found all over Europe in grain, flour, and flourproducts. One of the worst pests in Germany.

[0024] a2) Rice weevil (Sitophilus oryzae)=SITTOR

[0025] Size: 2.3-3.5 mm. Found in the tropics, the subtropics, and inwarm warehouses in Europe. Feeds on all types of grain and flourproducts. Feared storage pest in warm climates.

[0026] a3) Broad-horned flour beetle (Gnathocerus cornutus)=GNATCO

[0027] Size: 3.5-4 mm. Frequently found in mills, grain silos andbakeries. Beetles and larvae feed on grain and grain products.

[0028] a4) Saw-toothed grain beetle (Oryzaephilus surinamensis)=ORYZSA

[0029] Size: 2.5-3.5 mm. Common throughout the world, feeds on grain,flour, and grain products.

[0030] b) Wood Pests

[0031] b1) House longhorn beetle (Hylotrupes bajulus)=HYLOBA

[0032] Size: 7-21 mm. Feared pest; the larvae completely destroy oldpine timber used in buildings. House longhorn infestations have recentlyincreased significantly (due to the use of sapwood).

[0033] b2) Common furniture beetle (Anobium punctatum)=NOBPU

[0034] Size: 2.5-5 mm. Found in processed timber, old furniture, arttreasures.

[0035] c) American drywood termites (Cryptotermes brevis)=CRYPBR, andIncisitermes tabogae=INCITA

[0036] Size: 2.0-5 mm. These species are found primarily in the U.S.where they infest wooden houses and often cause severe damage if thehouses are not promptly treated.

[0037] Fumigants:

[0038] Trifluoroacetyl fluoride (TFAF),

[0039] acetyl fluoride (ACF),

[0040] chlorodifluoroacetyl fluoride (CFAF), and

[0041] SO₂F₂ (SF) (for comparison).

[0042] Procedure:

[0043] The test organisms, separated by species, were placed into aglass vessel measuring 30 cm×30 cm×60 cm, which was sealed with a glasslid so as to be airtight. The adults and the larvae of the mealwormbeetle (Tenebrio molitor) and the broad-horned flour beetle (Gnathoceruscornutus) were placed into small glass vessels approximately 5 cm indiameter, which were closed with a gauze lid and in which they couldfreely move about. The larvae of the rice weevil had burrowed into seedsof grain. The wood pest larvae were inserted into small blocks of woodmeasuring 5 cm×2.5 cm×2 cm. The openings were sealed with wads of cottonwool. Only one each of the larvae of the house longhorn beetle(Hylotrupes bajulus) was inserted into a piece of wood, while 6-8 larvaeof the common furniture beetle (Anobium punctatum) were inserted intoeach piece of wood.

[0044] The respective gas was then introduced into the fumigation vesselthrough a gas line from a gas tank that contained the specified amountof gas. After a defined time period, the fumigation vessel was purgedwith compressed air. The discharged gas was purified by an attached gasscrubber.

[0045] The beetles were observed until they died. This point wasrecorded for each species. The larvae of the wood pests as well as thelarvae of the rice weevil (Sitophilus oryzae) had to be picked out ofthe wood or the grain to check their condition. If any of the animalswere still alive, the wooden test blocks remaining in the vessel werefumigated again and were reexamined after the corresponding time spanhad elapsed. The same number of animals in the untreated control wasalso checked at each point.

[0046] The vitality of the animals was checked at certain timeintervals. The beetles could be observed through the fumigation vessel.This was also true for the larvae of the mealworm beetle and thebroad-horned flour beetle. The wooden test blocks of the wood pestlarvae were opened with hammer and chisel. Tweezers were used to pullthe rice weevil larvae out of the grain seeds. The exact time intervalsand the number of the evaluated pests were documented in the testresults.

Example 1 Use of Trifluoroacetyl Fluoride Against Wood Pests

[0047] 1st Fumigation 2nd Fumigation Air temperature 16° C. 13° C. Rel.air humidity 66% 66% Gas amount/vessel  2.74 g  2.9 g Gas concentration54.8 g/m³ 58.0 g/m³

[0048] Result: Time after Start of Fumigation 1 hr. 3 hrs. 24 hrs. 48hrs. Number Number Number Number Pests (Bayer) dead alive dead alivedead alive dead alive HYLOBA 4 2 6 0 — — — — HYLOBA — — — — 0 6 3 3larvae ANOBPU 6 0 — — — — — — ANOBPU — — — — 0 10 4 6 larvae

[0049] Exposed beetles and larvae were killed relatively quickly. After1-2 minutes, the animals became very active. After about 10 minutes, allthe beetles lay on their backs and only their legs and feelers weremoving slightly. Larvae without wooden test blocks were dead afterapproximately 1 hour. The gas does not penetrate the wood sufficientlywithin a time span of 48 hours to kill the larvae completely. Thebeetles and larvae of the control were all still alive.

Example 2 Use of Trifluoroacetyl Fluoride Against Wood Pests, AirCirculation Through Ventilators

[0050] 1st Fumigation 2nd Fumigation Air temperature 20.6° C. 21.5° C.Rel. air humidity 66% 56% Gas amount/vessel  2.88 g  2.40 g Gasconcentration 57.6 g/m³ 48.0 g/m³

[0051] Test with ventilator operation in the fumigation vessel Timeafter Start of Fumigation 1 hr. 12 hrs. 24 hrs. 48 hrs. Number NumberNumber Number Pests (Bayer) dead alive dead alive dead alive dead aliveHYLOBA 5 1 6  0 — — — — HYLOBA — — 0  7 0  7  1 6 larvae ANOBPU 6 0 — —— — — — ANOBPU — — 1 11 2 10 12 0 larvae

[0052] Even with ventilators, there was no improvement in theeffectiveness with respect to the larvae.

Example 3 Use of Trifluoroacetyl Fluoride Against Storage Pests

[0053] 1st Fumigation 2nd Fumigation Air temperature 17.2° C. 17.7° C.Rel. air humidity 54% 54% Gas amount/vessel  2.29 g  2.27 g Gasconcentration 45.8 g/m³ 45.4 g/m³

[0054] Result: Time after Start of Fumigation 1 hr. 3 hrs. 6 hrs. 12hrs. Number Number Number Number Pests dead alive dead alive dead alivedead alive TENEMO 15 0 — — — — — — TENEMO 15 0 — — — — — — larvae SITTOR20 0 — — — — — — SITTOR 15 5 20 0 — — — — larvae GNATCO 15 0 — — — — — —GNATCO 15 0 — — — — — — larvae ORYZSA 15 0 — — — — — —

Example 4 Use of Acetyl Fluoride Against Storage Pests

[0055] Air temperature: 19.3° C. Rel. air humidity: 54% Gasamount/vessel:  1.82 g Gas concentration: 36.5 g/m³

[0056] Result: Time after Start of Fumigation 1 hr. 2 hrs. 12 hrs. 24hrs. Number Number Number Number Pests dead alive dead alive dead alivedead alive TENEMO 10 0 — — — — — — TENEMO 5 5 10 0 — — — — larvae SITTOR25 0 — — — — — — SITTOR — — — — — — 25 0 larvae GNATCO 12 13 22 3 25 0 —— GNATCO 25 0 — — — — — — larvae ORYZSA 25 0 — — — — — —

[0057] In addition to the storage pests, 3 house longhorn beetles andlarvae as well as 2 common furniture beetle larvae were tested. Thehouse longhorn beetles were dead after 15 minutes.

[0058] After 24 hours, the larvae of the wood pests were dead. Anearlier effect, if any, was not determined because evaluation only tookplace after 24 hours.

Example 5 Comparison of Action of Acetyl Fluoride (ACF) and SulfurylFluoride (SF) on Wood and Storage Pests

[0059] 3rd 1st Fumigation 2nd Fumigation Fumigation Air temperature 23°C. 23° C. 22° C. Rel. air humidity 55% 55% 54% Gas amount/vessel ACF 2.53 g  2.41 g  2.57 g Gas amount/vessel SF  2.37 g  2.33 g  2.05 g Gasconcentration ACF 50.6 g/m³ 48.2 g/m³ 51.4 g/m³ Gas concentration SF47.4 g/m³ 44.6 g/m³ 41 g/m³

[0060] Result: Time after Start of Fumigation 30 min. 1 hr. 3 hrs. 6 hrsTest Number Number Number Number Agent Pest dead/alive dead/alivedead/alive dead/alive ACF HYLOBA  4 0 — — — — — — SF HYLOBA  0 4 2 2 4 0— — ACF HYLOBA — — 4 0 2 1 7 0 larvae SF HYLOBA — — 1 3 4 0 6 0 larvaeACF ANOBPU  6 0 — — — — — — SF ANOBPU  6 0 — — — — — — ACF ANOBPU — — 31 2 2 8 0 larvae SF ANOBPU — — 0 3 0 4 8 0 larvae ACF TENEMO 10 0 — — —— — — SF TENEMO 10 0 — — — — — — ACF TENEMO 10 0 — — — — — — larvae SFTENEOMO  4 1 4 1 5 0 — — larvae ACF SITTOR 15 0 — — — — — — SF SITTOR 150 — — — — — — ACF SITTOR — — 15 0 — — — — larvae SF SITTOR — — 15 0 — —— — larvae ACF GNATCO 15 0 — — — — — — SF GNATCO 15 0 — — — — — — ACFGNATCO 15 0 — — — — — — larvae SF GNATCO  0 15 15 0 — — — — larvae ACFORYZSA 15 0 — — — — — — SF ORYZSA 15 0 — — — — — —

[0061] Sulfuryl fluoride clearly acts more slowly than acetyl fluoride.

[0062] Conclusion:

[0063] Both acetyl fluoride and trifluoroacetyl fluoride are veryeffective against exposed beetles and larvae. Acetyl fluoride is veryeffective against wood pests, especially at temperatures in excess of20° C. (i.e., near or above the boiling point). It decomposes toharmless acetic acid with ventilation or can be converted to harmlessacetates with bases.

Example 6

[0064] Termite Control

[0065] Acetyl fluoride was used to control termites. A comparison testshowed it to be as effective as SO₂F₂. It was particularly effectiveagainst Cryptotermes. 3rd 1st Fumigation 2nd Fumigation Fumigation Airtemperature 23.7° C. 24° C. — Rel. air humidity 51% 66% — Gasamount/vessel ACF  2.50 g  2.69 g — Gas amount/vessel SF  2.39 g  2.24 g— Gas concentration ACF 50.0 g/m³ 53.8 g/m³ Gas concentration SF 47.8 g/m³ 44.8 g/m³

[0066] Result: Time after 1st Fumigation 30 min. 1 hr. 3 hrs. TestNumber Number Number Agent Pest dead/alive dead/alive dead/alive ACFCRYPBR 0 180 0 60 120 0 SF CRYPBBR 0 180 0 60 120 0 ACF INCITA 0 90 0 3060 0 SF INCITA 0 90 0 30 60 0

[0067] Although all fumigated termites were still alive after 1 hour,they were weakened and less lively than those of the control. Thetermites treated with sulfuryl fluoride were more lively overall after 1hour of fumigation than those treated with acetyl fluoride. After a24-hour observation period, these animals were reexamined. All of theCryptotermes treated with acetyl fluoride were dead. Only 3 out of 30 ofthe Incisitermes were still alive. All Incisitermes treated withsulfuryl fluoride were dead and 7 out of 60 of the Cryptotermes werestill alive. After 3 hours of fumigation, all animals were dead.

[0068] Overall, it can be stated that acetyl fluoride can penetrate woodmore quickly, and a slightly faster effect is achieved as a result. Thisbecame clear based on the termites examined within the described timeintervals. The animals fumigated with sulfuryl fluoride were somewhatlivelier than those treated with acetyl fluoride.

Example 7 Parallel Test—Acetyl Fluoride/Chlorodifluoroacetyl Fluoridefor Wood and Storage Pests

[0069] 3rd 1st Fumigation 2nd Fumigation Fumigation Air temperature20.0° C. 20.2° C. 19.8 C. Rel. air humidity 70% 65% 60% Gasamount/vessel ACF  2.65 g  2.73 g  0 Gas amount/vessel SF  2.18 g  2.07g  1.99 g Gas concentration ACF 53.0 g/m³ 54.6 g/m³  0 Gas concentrationSF 43.6 g/m³ 41.4 g/m³ 39.8 g/m³

[0070] Time after 1st Fumigation 30 min. 1 hr. 3 hrs. 6 hrs Test NumberNumber Number Number Agent Pest dead/alive dead/alive dead/alivedead/alive ACF HYLOBA 3 3 6 0 — — — — CFACF HYLOBA 6 0 — — — — — — ACFHYLOBA — — 3 2 10 0 — — larvae CFACF HYLOBA — — 0 5  0 5 0 5 larvae ACFANOBPU — — 1 5  4 2 2 4 larvae CFACF ANOBPU — — 0 6  3 3 2 4 larvae ACFTENEMO 10 0 — — — — — — CFACF TENEMO 0 10 0 10  0 10 5 5 ACF TENEMO 5 510 0 — — — — larvae CFACF TENEMO 0 10 0 10 10 0 — — larvae ACF SITTOR 150 — — — — — — CFACF SITTOR 8 7 8 7 15 0 — — ACF GNATCO 15 0 — — — — — —CFACF GNATCO 15 0 — — — — — — ACF GNATCO 15 0 — — — — — — larvae CFACFGNATCO 8 7 8 7 15 0 — — larvae ACF ORYZSA 15 0 — — — — — — CFACF ORYZSA15 0 — — — — — —

[0071] It is apparent that acetyl fluoride is superior tochlorodifluoroacetyl fluoride against several of the pest speciestested.

[0072] The foregoing description and examples have been set forth merelyto illustrate the invention and are not intended to be limiting. Sincemodifications of the described embodiments incorporating the spirit andsubstance of the invention may occur to persons skilled in the art, theinvention should be broadly construed to include all variations fallingwithin the scope of the appended claims and equivalents thereof.

[0073] Text of Referenced Section fromhttp://www.morse-assoicates.com/pressure.html Page 1

[0074] Relative Pressure in Work Area

[0075] The overall pressure differential between the work area andsurrounding areas should be specified. The work area should becontinuously maintained at an air pressure that is lower than that inany surrounding space in the building, or at any location in theimmediate proximity outside of the building envelope.

[0076] Any defects in the building exterior that may allow a highinfiltrations rate must be corrected before attempting to isolate arenovation work area with a pressure differential. Loose or crackedwindows and doors, damaged or worn weatherstripping, cracked or porouswalls, or holes will make the building interior extremely sensitive topressure changes due to wind. Such defects can be temporarily remediedby sealing with tape, plywood, strippable coating or caulking. Thissealing must be done before any sheet plastic is installed.

[0077] This pressure differential when measured across any physical orcritical barrier must equal or exceed the natural or mechanical forcesaffecting the work area.

[0078] 0.02 Inches of Water:

[0079] This should be adequate to isolate a work area in a one storybuilding where wind velocities are not expected to exceed 15 miles perhour, if windows and other infiltration points are well sealed. Thispressure differential can be easily maintained with normal procedures,air circulation rates and available equipment.

[0080] 0.03 Inches (0.75 mm) of Water:

[0081] This is the maximum pressure differential that is practical tomaintain without special practices. Sheet plastic barriers must bemechanically fastened to resist the skin stresses imposed by thispressure difference. In practice this will require diligence on the partof the contractor in maintaining critical barriers in place. Airinfiltration through penetrations in the building envelope, includingimproperly-sealed doors and windows, creates pressure behind the plasticthat pulls it loose. It may be necessary to seal some penetrations, suchas broken windows on the outside of the work area isolation.

[0082] 0.04 Inches (1 mm) of Water:

[0083] In tall buildings the effect of warm air rising produces a “stackeffect.” This effect predominates over wind pressures at heights around5 stories. This pressure differential should be adequate to isolate awork area in a one story building where wind velocities are not expectedto exceed 25 miles per hour, or a 5 story building where wind velocitiesare not expected to exceed 15 miles per hour. Special procedures arerequired to achieve and continuously maintain this pressuredifferential. Mechanical fastening of sheet plastic in a manner thatdistributes the loading at fasteners

[0084] Text of Referenced Section fromhttp://www.morse-assoicates.com/pressure.html Page 2

[0085] (plywood pads, duct tape edge reinforcement, etc.) is critical.This is the maximum pressure differential that can be measured with mostcommercially available pressure monitoring equipment designed forasbestos abatement work sites.

[0086] 0.05 Inches (1.27 mm) of Water:

[0087] The experience and technology necessary to set up and maintainpressure differentials at this level is available from the asbestosabatement industry in New Jersey. New Jersey requires a pressuredifferential of 0.05 inches of water (N.J.A.C. 5:23-8.19(c)) forasbestos abatement projects in occupied buildings higher than fourstories. This requirement has been in effect and regularly attainedsince 1993.

[0088]0.10 Inches (2.5 mm) of Water:

[0089] This is an upper limit on the pressure differential possible todevelop with portable equipment. Pressures differentials at this levelcould develop lateral forces high enough to cause damage to walls orother building elements. A pressure of 0.1 inches (2.5 mm) of water isequal to 0.52 pounds per square foot (24.9 Pa ) of surface area. Thispressure is high enough that partitions and other surfaces surroundingthe work area should be evaluated for structural adequacy. Achievingthis level will require specific and detailed design of enclosuressystems. Typically reinforced sheet plastic and structural reinforcingof barriers, subdividing of a large surface areas, and scrupulousdetailing of fastening systems will be required. Unless there areextenuating circumstances it is generally preferable to use a moremoderate pressure differential and local isolation as described below.

What is claimed is:
 1. A method of treating pests comprising subjectingsaid pests to an effective pesticidal amount of a carboxylic acidfluoride having a boiling point of less than 100° C. for a timesufficient to kill said pests.
 2. A method according to claim 1, whereinsaid carboxylic acid fluoride has a boiling point of less than 45° C. 3.A method according to claim 2, wherein said carboxylic acid fluoride hasa boiling point of less than 30° C.
 4. A method according to claim 1,wherein said carboxylic acid fluoride corresponds to the formula RC(O)F,where R represents CH₃, C₂H₅, CF₃, CF₂H or CF₂Cl.
 5. A method accordingto claim 1, wherein said carboxylic acid fluoride is used in admixturewith at least one additional pesticide.
 6. A method according to claim5, wherein said at least one additional pesticide is selected from thegroup consisting of sulfuryl fluoride, sulfuryl chlorofluoride,nitrogen, noble gases, CO₂, carbonyl sulfide, PH₃, alkyl phosphines,SF₆, inorganic or organic compounds with the CN group, organic esters,organic nitro compounds, halogenated hydrocarbons, alkynols, thiocyanateesters, isothiocyanate esters, chloropicrin, ethylene oxide, sulfonylfluorides and atomizing agents.
 7. A method according to claim 5,wherein said at least one additional pesticide comprises carbon dioxide.8. A mixture comprising at least one carboxylic acid fluoride having aboiling point of less than 100° C. and at least one additionalpesticide.
 9. A mixture according to claim 8, wherein said at least oneadditional pesticide is selected from the group consisting of sulfurylfluoride, sulfuryl chlorofluoride, nitrogen, noble gases, CO₂, carbonylsulfide, PH₃, alkyl phosphines, SF₆, inorganic or organic compounds withthe CN group, organic esters, organic nitro compounds, halogenatedhydrocarbons, alkynols, thiocyanate esters, isothiocyanate esters,chloropicrin, ethylene oxide, sulfonyl fluorides, and atomizing agents.10. A mixture according to claim 8, wherein said at least one carboxylicacid fluoride corresponds to the formula RC(O)F, in which R is methyl,ethyl, difluoromethyl, difluorochloromethyl or trifluoromethyl.
 11. Amixture according to claim 8, wherein said at least one additionalpesticide comprises CO₂.
 12. A mixture according to claim 11, furthercomprising at least one other pesticide.